ROCK CAN BE DIVIDED into sedimentary, igneous and metamorphic types. Sedimentary rock was formed by the compression of sediment, usually beneath water. The category includes both sandstones and limestones, which together form around 90 per cent of the walling stone used in British building, as well as shale and various conglomerates. Older sedimentary rocks, of the Carboniferous age, include Old Red Sandstone of the kind found in Devon, Herefordshire and Monmouthshire which were formed 350–400 million years ago. Younger sedimentary rocks include soft limestones such as chalk and clunch, or sandstones such as Reigate stone from Surrey.
Scotland’s geology is dominated by sandstone – and consequently so are its buildings. Craigleath stone, from Edinburgh’s largest quarry, was used extensively in its New Town from 1770 to 1830. Although gradually darkened by soot, the stone originally gave the City a pale brown-grey hue. It is the mineral content that is responsible for a stone’s colour. The reddy-brownness of ‘Hollington Red’, a Triassic sandstone from Staffordshire, or the burnt orange of East Anglian Carrstone, is the product of a high iron content. Some sandstones are easily carved, like that from the Kenton quarry which operated until the early twentieth century producing stone used extensively in Newcastle’s Grainger Town. Others, such as the gritstones from elsewhere in Northumberland, can be much coarser and hard to work.
Sandstone is not only used for walling, but is sometimes suitable for roofing. The stone must be reasonably fissile – splittable along its bed to form thin layers. Most of the sandstones used for roofing in Britain comes from Upper Carboniferous (Silesian) rock strata, including those from the Coal Measures and Millstone Grits found in the North Midlands, North of England and Scotland. Among them are the Elland Flags of Calderdale in west Yorkshire. In the South of England, Pennant sandstone, another Silesian rock, has been used in the area north of Bristol as well as in South Wales. Pennant roofing stones are relatively even and slender. They contrast in appearance with Horsham slabs found in Sussex and Surrey, which have a brownish colour and coarser texture and are from the younger Cretaceous strata. At the opposite end of the geological time spectrum are the Devonian rocks which produce sandstone roofing in places including Herefordshire and Orkney. The even more ancient Ordovican sandstone outcrop in Shropshire yields a coarse textured and characterful roofing stone found at places such as Acton Burnell.
Norfolk’s iron-rich Carrstone is often laid with the mortar set well back from the face of the stone.
New stone used to repair a weathered, early nineteenth-century façade of local sandstone in Berwick-upon-Tweed,
Sandstone and limestone are often easily distinguished, but the geological distinction between these two sedimentary rocks is sometimes slight. In the South East of England, a belt of ragstone runs from Folkestone across towards Farnham in Surrey. Ragstone is a hard and heavy building stone that can be worked but is more often used as rubble. It is technically a limestone, but its high silica content makes it a close relative of sandstone.
Limestone appears in pockets in Scotland – particularly in Mid- and East Lothian – and in South Wales but its greatest impact on Britain’s built landscape is in a belt that snakes northwards from Dorset to Yorkshire. These limestones, Oolites from the Jurassic period, contain shell fragments from the former sea-bed. At the southern end of the belt is the fine-grained and easily worked white limestone from the Isle of Portland. Further north, around Bath, quarries in places such as Box, Corsham and Bradford on Avon, supplied a warmer, cream coloured Oolitic limestone, used to create the classical detail of Bath’s Georgian buildings. Similar classical effects were achieved with the Oolitic Barnack stone at Stamford in Lincolnshire. Limestone from this area of the Midlands also includes the the pale cream-buff Clipsham stone from quarries near Grantham. At the northern end of the Oolitic belt, Ancaster provides a honey-cream coloured stone. Roofing materials can also be produced from Oolitic limestone, ranging from the coarse, brownish stone slates of the Cotswold, to the high quality Stonesfield slates of Oxfordshire, and the Collywestons of Northamptonshire, which tend to be darker and thinner.
Horsham slabs from Sussex, laid in courses that diminish in size from the eaves to the ridge. In the nineteenth century structural problems in a wing at Wakehurst Place (now National Trust) were attributed to the ‘heavy roofing of Horsham slabs [which] had so pressed upon the roof.’
An example of how Kentish ragstone was used as random rubble. In the Victorian period polygonal bond was popular for ragstone, where shaped stones were fitted together even more tightly than seen here.
Along with the Oolites, rocks of the Jurassic period include Liassic limestones from quarries such as that at Ham Hill in south Somerset. Ham Hill stone, from the upper Lias, gives towns such as Martock a distinctive orange glow. Hornton stone, a Lias from Warwickshire is sufficiently orange-brown to be known as ‘gingerbread stone’. Elsewhere in the South West, as well as in the Vale of Glamorgan and West Lincolnshire, Lias from the lower strata is a distinctive blue-grey. In north Derbyshire and around Tadcaster in Yorkshire, the limestone is Magnesian, from the older Permian period of rocks, and contains carbonates of magnesium rather than calcium. Magnesian limestone also produces roofing stone at places such as Whitwell in north Derbyshire. The oldest limestones, from the Carboniferous period, include the hard rubble used at Haddon Hall in Derbyshire. The youngest Cretaceous limestones include chalk, which is occasionally used for walls, such as those of Marsh Court in Hampshire designed by Edwin Lutyens, but is often considered too soft for external use.
Oolitic limestone roofing stone from the Cotswolds, showing high fossil shell content.
Collyweston in Northamptonshire has been a centre of stone slate quarrying for many centuries. These roofs in Collyweston village show how the relatively thin stone turned a greyish brown on weathering.
The warm, rich colour of local Ham Hill stone has shaped the character and appearance of Martock in south Somerset.
Chalk may be poorly suited to use as an external building stone, but does yield a distinctly British building material: flint. Flint appears as amorphous nodules in the Upper Chalk and at the top of the Middle Chalk beds. It is mostly formed of silica – extremely hard but liable to fracture. Its colour is determined by mineral pigmentation and ranges from brown to grey, though when newly cut slices are almost translucent. After release from the chalk by erosion or excavation, flint forms a white rind called the cortex. Flint is found chiefly in a band stretching from Dorset to East Anglia.
A pair of Hampshire cottages built with random rubble flint walling. Unusually, the flat arches over the window heads are also constructed from flint.
Large blocks of granite decoratively interspersed with smaller pieces in a distinctively Scottish pattern of masonry. Dumfriesshire.
While sedimentary rocks provide the bulk of materials for walling and roofing, other geological groups have not gone unused. Igneous rocks are formed from molten magma extruded from the earth’s core and have a crystalline structure. Particularly significant to building is granite, which has strong associations with Dartmoor and Cornwall, and with Aberdeen. Others include the dark and light Shap granites of Cumbria. Granite is hard and heavy, with colours ranging from pink to grey. Polyphant, another hard igneous rock, is found and used in the area around Launceston in Cornwall.
‘True’ slate is a metamorphic rock, originally a clay or sedimentary mudstone transformed by massive pressure from the earth. Where found locally it has a long history of use for the walls and roofs of buildings, but from the late eighteenth century slates from areas such as north Wales began to be transported greater distances. Slate production may be strongly associated with Wales, but is not exclusive to it. English slate – that is ‘true slate’ rather than fissile stone like Stonesfield – tends to be thicker and heavier than Welsh varieties. This is the case in Westmorland, where the slate is greenish and weighty. Scotland had a strong domestic slate industry, producing material such as the purple-green slates of Aberfoyle, though its production was eclipsed by Wales in the late nineteenth century. Slate also has a strong presence in Cornwall, from quarries like that at Delabole.
Cutting large blocks of granite at the Rubislaw Quarry, Aberdeen, 1907. The Londoner sending this postcard wrote how ‘it seems very strange here, all the houses are built of granite.’
The conglomerate, known as Septaria, is found and used for building in coastal areas of Essex and Suffolk. It is combined here with smaller pebbles.
Some stones used for building have been moved from their geological place of formation. Erratics, such as the metamorphic Sarsens found sometimes in buildings on the Salisbury Plain, were shifted by glacial movement. Pebbles moved and modelled by the sea have been used for construction in coastal towns such as Brighton and Happisburgh in Norfolk. In Essex and Suffolk, the shoreline has yielded a local stone called Septaria, a brown, clayey conglomerate, rounded by the sea and very young in geological terms. River boulders have found uses too and are encountered in buildings in upland Wales, Scotland and in the Lake District where they are known as ‘beck stones’.
Pebble walling used alongside refined classical detailing in a Regency house in Brighton. The pointing between the pebbles is a modern cement-based material.
Cornish Delabole slate laid in diminishing courses on a house roof in the north of the county.
Very often rock is found in strata tilted and undulating as a result of geological movement. This, combined with subsequent erosion which may leave lower layers exposed, often forms a complex geological landscape. It means, in Britain, that rocks of similar geological age and type may appear at separate locations or, like the Oolitic limestone belt, may stretch across a considerable distance. This geological pattern has been important to the quarrying history of Britain, but other factors have also been significant. Some stones are far more suitable than others for building because of their durability or workability. Where good building stones can be readily extracted a centre of quarrying has often developed, though even then the extracted material may not be of a uniform standard. At Headington in Oxfordshire, it was noted in 1819 that the stone ‘varies much in quality, the soft and the hard lying indiscriminately mixed’. Stone is also, of course, a finite resource. Deep beds of Purbeck ‘marble’ (technically a polished limestone) used for long column shafts in the medieval period are now hard to find. Historic Scotland estimate that there may be as many as 12,000 old quarry sites in the country, although perhaps only 750 produced stone of great quality.
In the pre-industrial age, transportation of stone from the quarry site was as much an issue as its extraction. Stone was sometimes moved significant distances, but this tended to be for the most expensive building projects. When Waltham Abbey in Essex required substantial quantities of stone for building in 1218, it obtained them from a quarry near Reigate in Surrey. The stone was transported via a specially built wharf at Battersea and along the Thames. Before the late eighteenth century stone was not normally carried more than 10–20 miles from the quarry site. Even this was a considerable undertaking where the terrain was difficult. Into the mid-nineteenth century Kentish ragstone, for example, was estimated to cost 1s 6d per ton at the quarry, but 5s by the time it arrived in London. Canals, then railways brought change. Sir George Head commented in 1835 that ‘The banks of the Liverpool Canal [near Leeds] ... are continually covered with [local stone] ... in all various sizes and dimensions’. The stockpile of stone waiting to be despatched in 1893 from one railway station in the Bath stone quarrying district was estimated at half a million cubic feet.
Before stone could be carried to site it had to be obtained from the ground. Sometimes it might simply be available from the surface. In many areas this came as a by-product of farmland clearance. Cotswold and Oxfordshire roof slates were known as ‘presents’ when they were collected from the land without the need to be split from larger stones. Where stone did not lie on the surface, only marginally more effort might be needed to make it available. Shallow quarry pits were often dug beside the place of construction. This ‘delving’ for materials was common in areas such as Herefordshire, when roofing stone was needed.
Where greater excavation was required, a careful economic decision would need to be made about the viability of readying the site for extraction below the surface. When visiting Blackburn in 1801 Thomas Pennant wrote of a stone that ‘had long been neglected on account of the expense of taking off the incumbent strata, which increased so as to deprive the adventure of all profit.’ Not all stone caused such trouble. Sir George Head found that ‘at Bramley Falls, three miles from Leeds, the stone [a hard, durable sandstone] ... is quarried with remarkable facility.’ At the Wodehouse quarries nearby, perhaps underrating the skill of the quarrymen, he concluded that extraction was even simpler: ‘lying naturally in horizontal layers, and splitting in a parallel direction by the slightest blow of the chisel ... the workmen have nothing to do but raise the blocks from the quarry.’
The business of stone extraction and preparation required varying degrees of skill. Cotswold stone slate production was highly seasonal, drawing in temporary labour when necessary. While two or three workers might be permanently employed to dress the slates, thirty or forty more might be used over the winter, when agricultural demand was slack. This seasonal labour was required because of the role of frost action in roofing slate production. With Stonesfield slate from Oxfordshire, the unfrosted stone, known as ‘pendle’, had to be kept wet under earth before the winter. Then, when frosts were sufficiently hard a workforce would be required to unearth and lay out the pendle. The frost would then act upon the still-damp stone, splitting it along bedding planes to a thickness that could be used for roofing. Slate workers would then shape the stones, as well as holing them with a slating pick so they could be hung in place.
A late nineteenth-century view of one of the quarries at Swithland, Leicestershire, after its closure. Stone for roofing and walling had been extracted at Swithland and nearby since the Roman period.
Edwardian Slate workers in north Wales. Michael Farraday commented in 1819 that ‘The men work with astonishing rapidity cutting the slate as if it were a wafer.’
Walling stone sometimes required much deeper excavation. In total there are around 60 miles of quarry galleries in the hills near Bath, some hundreds of feet deep. In these deep quarries the traditional method of extraction initially involved ‘picking the breach’ – that is removing a horizontal section of stone just below the gallery roof. A first block – the ‘wrist stone’ – would then be sawn out, allowing the quarrymen access to cut out subsequent blocks from the rear, using a shallow-bladed saw. Pillars of stone would be left in position for support between the area being worked – the ‘breach’. Blocks would then be pulled up the sloping shaft by horse to the surface.
Where stone was extracted from pits, traditionally it was split by use of a metal plug and feathers, fitted into drilled holes, which caused the stone to fracture. Earlier, wooden plugs had been used which expanded when wet to the same effect. These methods continued into the industrial age, although by the early nineteenth century blasting was sometimes used, despite the risk of damage to the stone. In 1834, at Edinburgh’s Craigleath quarry, ‘Blasting rock on a large scale was tried out … The explosion caused a massive fissure five to ten feet wide and fifty feet deep and 8–10 thousand tons of stone was dislodged from the solid rock.’ Blasting brought new and obvious dangers, but these had always been present in a quarrying environment. Coroners’ records from north Wales in the earlier-nineteenth century feature many casualties, like John David Price of Llanbeblig who was ‘crushed by a large portion of slate that fell from the top of Cae Coch Quarry’ and Henry Jones of Llandygai, ‘who fell over a precipice’.
Quarryman ‘picking the breach’ between the gallery roof and the block of stone to be removed. Corsham, Wiltshire, 1928.
Map from The Builder showing the large number of Oolitic limestone quarries around Bath and the railway network that, by 1895, assisted stone transportation.
The Penhryn ‘true’ slate quarry in north Wales. One nineteenth-century observer noted of a horse assisting quarrymen at the precipice edge that it ‘had worked so long with the men that a degree of mutual intelligence prevailed between both; in the meantime the expression of his eye and ear showed him to be aware of the danger.’
Stone has often been prized as a constructional material but it varies greatly in its suitability for building. Kentish ragstone, for instance, provides a durable rubble but is not generally favoured for carving or use as a lintel spanning an opening. Flint is largely impervious to damp and decay and so good for plinth walls, but not easy to form into arches. While masonry techniques could help overcome deficiencies of stones, an alternative was to combine different types in one building. An easily carvable freestone could be used for decorative surrounds to doors and windows, while a cheaper but less workable rubble might be used for plain walling. A Cornish building contract of 1776 set out how different stones were to be used: ‘The front wall to be Breage Cliff stone or any other Moor stone ... and other walls to be built of Quarry Stone with Moor Stone Coiners or Coyns [quoins] ... the roof to be covered with best Denaboyle [Delabole] slate.’ The Breage or Moor stone here was granite, and the Quarry Stone was probably local killas, a softer metamorphic rock of sedimentary origin. The nature of the stone would also affect the final form of the building. Larger roofing slabs, like those from Purbeck, which might be up to 36 inches long, could cope with a relatively low roof pitch of 30–40 degrees, but roofing stones from the Cotswolds, which tended to be smaller, required a steeper pitch of 50 degrees or more.
The costs and effort involved in stone extraction meant that as little as possible was discarded. Waste material from the roof slating industry in North Wales could still be valuable for the walls of local buildings. In Scotland, snecked rubblework employed small pieces of stone among larger ones to fill gaps and even-up courses. Similarly, flakes of flint and other stones were used for the process of galleting which decoratively filled wide joints. With stone for roofing, production in a range of sizes helped minimise waste. The resulting slates were given names according to their dimensions. In the Pennines, names included ‘scant bachelors’, ‘wippetts’ and ‘fairwells’. True slate sizes had names such as ‘Duchess’ (24 x 12 inches) and ‘Lady’ which was half this size. Slates in a range of sizes were laid on roofs so that courses diminished from the eaves (bottom of roof) to the ridge. Larger stones with fewer joints could better cope with the run off of water which was concentrated at the roof’s base. Where available, exceptionally large stones could further reduce the risk of water penetration. In the north of Scotland and Orkney islands, enormous flagstones up to 10 feet long were sometimes used. Near a stone quarry at Bradwell in Oxfordshire, a seventeenth-century observer noted how he had ‘seen a small hovel that for its whole covering had required no more than one of these [large] stones.’
Sandstone, galleted with smaller pieces of sandstone set in the joints from Cromarty in the Scottish Highlands.
In the nineteenth century, when speculative builders were attempting to minimise costs, stone façades were sometimes extremely slight and the thickness of just one stone block. Generally though, traditional stone walls were constructed with two ‘skins’ of masonry, and a core of rubble. Some stones were laid across the wall’s full width to bond the whole together. Stone, if of suitable type, could also be used for details such as projecting cornices or for the coping stones on the top of gable walls – known as ‘skews’ in Scotland. Flint and pebble walls were constructed in a similar way, with two skins and a rubble core, though other types of stone or alternative materials were normally used for quoins, lintels or surrounds. Drystone building – that is construction that uses little or no mortar between the stones – was usually a technique restricted to boundary walls or outbuildings but there is some evidence from Wales and Scotland for its use in houses. In Cumbria, stones were often angled downwards with the mortar recessed back, giving a ‘dry stone’ appearance, but this was probably done chiefly to reduce erosion of the mortar in a harsh climate.
Random rubble ironstone from Surrey. The technique of galleting, or setting small stones in the mortar, was both decorative and practical. It reduced the width of the joint and the ratio of mortar to stone.
The corner collapse of this coursed rubble flint wall reveals a core of flint, brick and lime mortar.
The finish of the wall depended on the type of stone, available funds, and the mason’s skill. Most desirable was ashlar work, where blocks were carefully squared by the mason in order to fit together with a neat, tight mortar joint often no more than a few millimetres thick. If ashlar work could not be afforded throughout, it might be reserved for quoins or other details. In between, sections of plain walling could be rubble stone, laid in courses or more randomly. Flint too, though of haphazard form in its natural state, could be worked in a variety of ways. An 1820s survey of Norfolk mentioned that flints ‘when squared or layed with care are extremely beautiful’, though they had ‘little bond’. At the simplest, flintwork could be coursed or uncoursed, like rubble, but it could also be squared to form a more regular effect or even laid in herringbone or chequerwork patterns.
Squared coursed rubble laid in bands to exploit the white and iron-rich orange colours of the local stone in Rutland.
A ‘true’ slate roof grouted externally with lime mortar. This example is from north Devon, but the technique was used in other parts of the South West and in Wales.
Stone or ‘true’ slates would be fixed to battens, supported by a timber roof structure. Some stone slate had a considerable life expectancy and larger slates might be cut down for re-use when damaged. By the nineteenth century, ‘true’ slates could often be of a single size over the whole roof, in contrast with older traditions, such as scantle slating, which used random sizes and diminishing courses. The lightness of ‘true’ slate also made it suitable to use for the cladding of walls. Slate hanging, supported on battens fixed to the wall, was particularly popular in the South West, Wales and in coastal areas where protection from driving wind and rain was important.
Rubble work might be within the capabilities of a general builder or farm worker, but more sophisticated masonry required years of training. In the Architectural Magazine of 1834, John Claudius Loudon wrote that in areas like Scotland where stone predominated, ‘the mason very frequently takes the lead of the carpenter, more especially in buildings of the humbler class, because the facings to doors and windows, the projecting stones of quoins, the crow steps on gable ends, and the ashlar work of chimney tops ... require no moulds or guides from the carpenter.’ Today stone cut to size is often supplied direct from the quarry, but preparation of the stone was traditionally part of the mason’s training, along with its fixing, and even the setting up of scaffolding. Shaping the block of stone is known as banker masonry. The ‘banker’ is a stone – usually covered with a soft protective material, such as carpet – on which the block is worked. The banker mason must first square the block. This technique, known as boning out, involves levelling and squaring each side in turn. Dimensions of stone are always set out by face, then depth, then bed height. Traditionally, to remove large areas of waste stone a saw might be used or more often a mallet and chisel. A range of chisels was employed, including the punch, waster and bolster, allowing progressively finer control of the cutting. Chisels, more like those of a carpenter might be used for soft stone. The final surface of softer stone would be prepared with a bladed ‘drag’. With ashlar blocks, a range of final finishes could be achieved. These included tooled diagonal lines, but might involve more sophisticated rusticated or vermiculated effects, of the kind often specified for the plinths of classical building in the eighteenth and nineteenth centuries.
Stone being worked in a banker mason’s shop before being fixed in place on a building. Note how the stone is protected from damage by carpet on the banker.
This graffiti, carved into soft chalky clunch used for ashlar walling in Hertfordshire, features the date 1777.
A selection of mason’s tools as depicted in Mitchell’s Building Construction of 1909, including wedge and feathers for splitting stone and lewis for use when lifting blocks.
With the carved or moulded forms needed for cornices, door surrounds or window mullions, templates and a scriber for marking would be needed to set out the required profile on the squared stone. Medieval masons’ templates were likely to be wooden; in the nineteenth century steel was normally used; now plastic or zinc is common. Templates can be reused and so are usually hung up carefully in the banker’s shop to avoid damage. Moving stone around the mason’s yard and onto the building site required special care, in view of the weight involved and danger to both the stone and masons. A chain hoist and trolley could be employed to move heavy stones, attached by a lewis. A hole is drilled in the stone and the lewis, which is a pronged metal fixing, expands into the hole on lifting.
Lifting a stone block using a chain hoist and a lewis fitted into a hole in the stone. As one nineteenth-century commentator wrote: ‘By this apparently small a purchase ... it seemed astonishing how so heavy a mass could possibly hold together.’
Finely cut stonework used for ashlar blocks and carved architectural details on a classical Georgian façade at Stamford in Lincolnshire.
The cut stone would be laid in place by the fixer mason, whose tools included trowels and a spirit level. Stones would be placed to form a strong bond, with vertical joints staggered, and would generally be fixed with mortar – a slender joint in the case of ashlar, but usually much wider in rubblework. In some cases, alternative or additional methods of fixing would be employed. These included a joggle (a small projection which fits into a corresponding recess in the next stone, used to resist sideways pressure) or a metal cramp (often used for extra joint strength in cornices or thin facings). Where an arch was required, the pre-cut stones would be positioned with the aid of a timber former, which would hold the stones in position until the central keystone was in place.
In the case of flint, the material would be prepared by a knapper. Knapping is a prehistoric skill, though in recent centuries metal tools, such as flaking hammers, have been introduced. The knapper could produce around twenty finished flints per hour, though much more time would be needed if they were to be carefully squared rather than roughly faced. The flint was examined for natural fissures before being held between the knees and hit with the hammer. Flint, boulder and pebble walls were built up slowly, allowing the mortar to dry between ‘lifts’ (the extent to which the construction rose vertically). If the wall was to be strong, lifts were rarely more than a foot at a time.
Roofing slate was likely to be prepared at the quarry site, rather than the building site. In 1787, for instance, Thomas Colley of Collyweston was contracted to deliver dressed Collyweston stone slates to the building site of Mr Turner, a slater of Grantham, at £1 13s 4d per 1,000. ‘True’ slate was similarly prepared at the quarry. It would be laid on a cutting dog, held between the knees, and hit with a handled, heavy, metal blade called a zax to trim the edges. Holes for hanging the slate would be made with a pointed hammer. Differing local techniques were used for the laying of stone roofs. The earliest slates in Wales seem to have been laid on a bed of moss, where today a waterproof felt would be used. More commonly, mortar ‘torching’ of the underside of the roof was used to help prevent water penetration. The slates, particularly where of stone or of randomly sized scantle ‘true’ slate, would sometimes be pointed with mortar on their upper face too. Crucial to the performance of all slates is the lap, measured as the distance between the tail (bottom edge) and the top nail hole of the one it covers. Fixing methods have changed greatly over time. Uneven or small scantle slates might have only one hole at the top, but ‘true’ slates of more regular sizing often now have holes either side at their mid-point. Non-ferrous nails are commonly used today, whereas in the recent past nails were iron, and this has often caused failure of the roof within the lifespan of the slates themselves. Older materials for fixing included oak pegs, or even sheep’s bones.
Carefully cut sandstone ashlar walling with a tooled finish. Note the fine joints and edges with tooling at 90 degrees to that on the rest of the block.
Dressing the edge of a Herefordshire sandstone slate. Small scale delving (quarrying) for stone slate has been revived in the county in recent years.
Cotswold stone slates, laid in diminishing courses and with a swept valley between roof slopes.
A close-up of pargetting on a house in Suffolk. A wide range of patterns could be incised in the wet plaster for decorative effect.
